Tribological investigation of Ni-graphene oxide composite coating produced by pulsed electrodeposition

Nickel-graphene oxide (GO) nanocomposite coatings with a uniform grain distribution were prepared on the SS440 samples and SS ball surface by pulsed electrodeposition (PED) method. The morphology, compositional, and tribological properties were investigated. FE-SEM and AFM microscopic studies shows a homogenous presence of GO particles intercalated in the Ni matrix in the composite coating. The incorporation of GO into the Ni matrix reduced the water contact angle of the coating showing its hydrophilic nature. XRD, EDS, and Raman spectra also confirmed the presence of GO on the coating surface as well as inside the matrix. The tribological studies show that the trapped GO particles positively affect the friction and wear resistance of the coating through formation of a tribo film in the contact interface. The effect of sliding speed on COF and wear rate of the pristine Ni coating was compared with Ni-GO composite coating and the insertion of GO into Ni matrix is found to reduce the coefficient of friction and wear depth of the coating substantially. With increasing sliding speed, the wear depth is almost 10 times lesser than pristine Ni, thus indicating its antiwear characteristics after intercalation of GO particles in the Ni matrix.